Telephone system



June 2, 1936. R. l.. sToKELY.

TELEPHONE SYSTEM Filed Oct. l1, 7 Sheets-Sheet 1 /NVENTOR R. L. sro/(EL y ArroR/VEV June 2, 1936. R. l.. sToKELY TELEPHONE SYSTEM Filed Oct. 1l, 1954 '7 Sheets-Sheet 2,

NEN

la! QN SN ATTORNEY June 2, 1936. R STQKELY 2,042,561

TELEPHONE SYSTEM Filed Oct. l1, 1934 7 Sheets-Sheet 3 /lQ/ROTARY srsp $1? www@ /NvE/vroR BV R. LSTOKELV A TTORNEY Filed ook.

l1, 1934 '7 SheetS-Sheerl 4 /NVENTOR R.L.$7`OKELV @y 7436. 5.775

ATToR/s/Ey4 Y Jurne 2, 1936; R. L. sToKELY 2,042,561

TELEPHONE SYSTEM Filed Oct. ll, 1934 v 7 Sheets-Sheet 5 -1 N E 9' "u i Q N.

/NVENTOR L. STO/(FLY BV ATTOR EY June 2, 1936. 2 R. s'ToKELY A 2,042,561

TELEPHONE SYSTEM Filed Oct. 1l,` 1934 7 Sheets-Sheet 6 LSTO/(EL-V `Arrow/Vn R. L. STOKELY TELEPHONE SYSTEM `lune 2, 1936.

Filed Ooi. 11 1934 7 sheets-sheet `7 IIHII lu Nm A u) /N VE N T OR R. L. sro/(ELK ATTORNEY Patented June 2, 1936 A UNITED STATES PATENTv OFFICE TELEPHONE SYSTEM Ray L. Stokely, Floral Park, N. Y., assignor to- Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application October 11, 1934, Serial No. 747,831 17 Claims. (Cl. 1794-71) This invention relates to telephone systems of an idle time and zone-metering equipment for and particularly to measured service telephone use in chargingfory the call.

systems. A telephone system in which the invention is The object of the invention is to provide a reembodied is shown in the drawings which form a liable and economical arrangement for registerpart of this specication. The use of the inven- 5 ing variable charges for telephone service. tion/is, however, not limitedto the particular` sys- In multi-oflice automatic telephone systems tem shown and other applications of the invenwhich provide measured service, the charge for a tion will readily occur to one skilled in the art.

call may vary in accordance with the location of Referring 110W t0 the ClIaWiIlgSZ the called line with respect to the calling line and Fig. 1 SHOWS a Calling SulOSCi'ibeTS Station A. a l0 in accordance with the duration of the call. It line finder LF-l, a charging trunk CT-l peris usual in such systems to provide meter operatmanently connecting the finder LF-l to a first ing means in a trunk included` in the talking conselector S-I, an intermediate selector S'-2, a

nection between a calling line and the first imconnector C-l, and a called subscribers station l5 pulse responsive selector switch employed in es- B-the trunk CT-l iS fOr 115e With message-Tate 15 tablishing connection with a called line. Means subscribers lines; for indicating the zone or location of the called Fig. 2 shows a repeater R-I associated with an line is commonly located in the outgoing trunk nteroiliee trunk T-L an incomingselector S-3 repeaters, and timing mechanism for measuring to which, the distant end' of trunk T--l is conv off the periods of time, for each of which a charge, nected, a connector C-2, and accalled subscribers 2,0

is registered, is commonly located either in the stationC; outgoing repeater or in the charging trunk. Fig. 3. shows a trunkrflnder TF, the terminals.

According to this invention, zone metering and in its bank being COImeCted t0 Charging trunks timing equipment is provided in an automatic tel- Such as and including the trunk CT-I of Fig. 1;

ephone system for operative association with any Fig. l shows a zone. metering and timing ap- 25 one of a plurality of charging trunks. paratus Z-I which is individual' to and per- According to this invention, switching means manently associated with the trunk. nder TF are provided for associating an idle zone meterand which is arranged for use in a system i11- ing and timing unit with a charging trunk leading Cllldlng. repeaters SuCh aS R/ l ShOWn lill Fig- 2;

to arst selector switch on calls involving an out- Fig. 5 shows a repeater Rf-2 aSSOCiated With 30 going repeater, zone indicating signals being an iDteI'OfiCe trunk T2, an iiCOI/liilg` Selector thereupon transmitted from the outgoing trunk S--4' to which the distant end of trunk T-2 is repeater for recordingin the zone metering and COIlIleCted, a COIlIleCtOI C-3 and a Called Subtiming unit. A feature of the invention is a trunk scribers station D;

finder switch for connecting an associated time Fig- 6 ShOWS a Zeile metering and timing aD- 35 and zone metering equipment to the charging 'paratus Z-2 fOI' use in a System nClllding the trunk leading to a rst selector, such a connecrepeater R-2 Shown in Fig. 5; tion being established in response to a signal from Fig- '7 ShOWS a Calling SilbSClibe1 "S Station E.` a the outgoing trunk repeater circuit through which line finder 11F-2, a Charging trunk CT--Z per-- the provision of means, in suon a time and Zone selector S-5, an intermediate Selector S-6, a metering equip-ment, operative in response to its connector C-ll and a called subscribers station connection with a charging trunk for transmit- F; for at-rate Subscribers lines; the Charging ting a signal to the outgoing trunk repeater trunk arrangement ShOWn in Fig. '7 isused in 15 through which the call is being completed to DlaCe 0f that'SllOWIl in Fig- 1; 4.5v

initiate the transmission of zone indicating sig- Figs. 8 and 9 show how Figs'. 1 to '1, inclusive,

nals from the outgoing trunk, these signals being Should be placed t0 ferm Operative arrangements. registered in the time and Zone metering ap-. The line nder, selector, connector and trunk paratus. nder switches shown in the drawing are all of 5o Another feature oi the invention is a message the Well-knOWll iWO-mOtiOIl StI'OWgeI" type and 50 rate charging trunk arranged to operate a calling each of these switches is represented in the drawsubscribers meter once on local calls and aring by a set of brushes and one or two sets of ranged to initiate, in response to a signal received terminals. The trunk finder TF is shown comfrom the outgoing repeater through which an plete but the broken lines leading to the brushes .to the call is being completed. A further feature is manently connecting the nder LF-Z to a first 40 5 interoice call is being completed, the connection off the other switches represent apparatus and 55 as to selectively V Yscribers dial and is connections which have been omitted. For a complete description of the line finders LF-I and LF-2 reference may be had to my Patent No. 1,799,654, granted April 7, 1931. For a complete description of the operation of the selector and connector switches reference may be had to pages 53to 67, inclusive, of the second edition of Automatic Telephony By Smith and Campbell, published in 1921.

The charging trunk CT-I (Fig. 1) Vis arranged for use with message-rate subscribers lines and comprises the usual polarized supervisory relay |04 operable by a reversal of current in response to the removal of the receiver at the called subscribers station to initiate metering, a. relay |06 responsive to the vconnection of booster-battery potential to the sleeve conductor |29 on interzone calls to start an idle trunk finder such as 'I'F through which the trunk CT-l is extended to an idle zone metering control unit Z-I (or Z-2) The trunk CT-I also includes a relay |3, the operation of which connects booster-battery potential to the sleeve conductor |21 to operate the calling subscribers meter.

'I'he charging trunk CT-2 (Fig. 7) is arranged Y for use with ilat-rate subscribers lines .and comprises the usual polarized supervisory relay 104, a relay |06 responsive to the connection of boosterbattery potential to sleeve conductor '|29 on inter-zone calls to start an idle trunk nder 'IF by which the trunk CT-Z is extended to an idle zone metering control unit Z-I (or Z-2) The repeaters R-I and R-2 and the zone metering control units shown in the drawings are adapted for use in systems having ve charging zones but may be modified for use with systems having any number of zones.

The repeater R.-| comprises a line relay 20| a register switch J-|, means responsive to the answer of the called subscriber for transmitting a signal to the charging trunk to initiate the association of a zone metering control unit with the charging trunk, and interrupter controlled means for 'transmitting zone indicating signals over the *sleeve conductor, through the charging trunk CT--l (or CT-Z), to the zone metering control unit to which the charging trunk is connected. 'I'he line relay 20| responds to the dial impulses created by the operation of the calling subeffective to repeat these impulses over the trunk T l to control the selective operation of the succeeding switches employed in completing the desired connection. Relay 20| also repeats the impulses created by the dialing of the rst digit to advance register switch J-I to a corresponding position, which'position is ndicative of the zone within which the called line is located. The register J-l may be modified so respond to more than one digit in case the registering of one digit is insuicient to determine the zone within which the line of a called subscriber is located.

The repeater R-2 is similar to the repeater transmit upon seizure, a signal to the charging trunk CT-I (or CT-2) to indicate that the call is an interoice call without waiting for the called subscriber to answer.

The zone metering and timing unit Z-l is arranged for use with repeater R-l and comprises zone register relays 402, 403, 404 and 405 which are eiTective upon operative connection of the unit with a charging trunk to register the zone within which the called line is located as indicated by the signals received over the sleeve conductor period. These control units may,

except that it is' arranged to immediately of the charging trunk from the repeater. Upon removal of the receiver at the called station, as indicated by the operation of the polarized supervisory relay of the charging trunk, the control unit is effective to initiate the advance of the timing switch M I to cause the operation of the calling subscribers meter once, twice, three times, Y

the operation of the zone register relays 602,

603, 604 and 605.

As shown, the zone metering and timing control units Z-I and Z-2 are arranged so that the charge for each overtime period is the same as for the initial period .and so that the length of an overtime period is the same as the initial however, be readily modified so that the overtime charge may vary both in the number of meter operations and in its duration from the initial charge. A table I;

showing six of the many possible charging plans which may be used in systems having five zones is found in my Patent No. 1,859,941, granted May 24, 1932.

The interrupter I-I in Fig. 2 and interrupter I-2 in Fig. 5 are similar, the reference characters being the same for corresponding elements except for the hundreds digit. All of the drums of each interrupter may be mounted on a common driving shaft. In any event, all of these drumsY have a three-second cycle of rotation. Referring to interrupter I-l, drums 221, 228, 229, 232, 233, 234 and 235 connect their brushes to ground once per cycle. The closure through drums 221, 229, 232, 233, 234 and 235 begins simultaneously. The closure through drum 221 endures for .5 second, the closure through drum 229` endures for .75 second, drum 232 endures for 1.25 seconds, the closure through drum 233 endures for 1.75 seconds, the closure through drum 234 endures for 2.25 seconds, and the closure through drum 235 endures for 2.75 seconds. The closure through drum 228 begins two seconds after the closure through drum 22T terminates and endures for .5 second.

The brush of drum 230 is connected to ground four times per cycle, each closure enduring for .25 second; the first closure occurs .25 second after the closure through drum 229 terminates and .25 second elapses between the end of each of the rst, second and third closures and the beginning of the second, third and fourth closures, respectively. The interrupters I-l and I-2 are common to a plurality of charging trunks, -a plurality of repeaters and a plurality of zone metering control units.

The operation of the system comprising Figs. 1, 2, 3 and 4 will be described, it being assumed that a call is originated at the message-rate subscribers stationA. The line |00 is thereupon extended through the brushes of a line finder LF-I, through the associated charging trunk CT-I to the line relay (not shown) of the associated first selector S-I in well-known manner. Upon connection of a holding ground pothe closure through' tential from selector S-2 to sleeve conductor |29, relay |05 is operated' thereby connectingthe sleeve conductor |21 of trunk CT--|', through. its left front' contact, the backV contact of the right continuity spring of relay |08, and through impedance to ground at theinner right: back contact. of relay ||0. This connection to ground serves to hold the cut-off relay |01 operated and to prevent the return of the'. line nder'LF-I to normal. Relay |06 is marginal and doesnotY operate when ground potential is connected to conductor |20.v In response to the impulses`v created bythe dialing of the rst digit of the numbersof the subscribers station. with which' connection is desired, the selector'S-l operatesY to select a set of terminals in the corresponding level of its bank, which set of terminals connect to an idle trunk |31 leading to` a second selector S-2 in the same office or connect to a trunk |38 leading to a repeater R-I` and thence over an interoice trunk T-I to an incoming selector S-3 in another office.

If the called station is in the same office as the calling station, the impulses created by the dialing of the succeeding digits of the called subscribers number control the selective operation of a second selectors-2, the selective operation of intermediate selectors, if any, and the selective operation of a connector C-I to establish connection with the line leading to the called station B. The called station is-signaled in the usual manner and when the call is answered the usual reversal of current in the talking conductors of trunk CT|, and line |00 cause the operation of the polarized supervisory relay |04. The operation of relay |04 connects the left winding of relay ||3, through the outer right back contact of relay |08, back contact of relay |06, outer left back contact of relay H0, front contact of relay |04, outer right back contact of relay ||0, back contact of the right continuity spring of relay H3 over conductor |3| to the brush of drum 221 of interrupter I-|. As soon after relay |04 operates as the brush of interrupter drum 221 is connected to ground, relay ||3v operates and closes a locking circuit through the front contact of its right continuity spring to ground at the outer right front contact ofrelay |05. Relay ||3 also connects its right winding in parallel with the winding of relay |08V over conductor |32 to the brush of interrupter drum 228 and closes a circuit for operating relay |09. 'When the brush of interrupter 228 is next connected to ground, approximately but not less than two seconds after relay ||3 operates, relay |03 is operated and the right winding of relay ||3 is energized to hold relay I3 operated. Relay |08 locks through the front contact of its continuity spring to ground at the outer right front contact of relay |05 and opens the circuit through the left winding of relay H3. With relays ||3, |09 and |00A all operated, a circuit for'V operating the calling subscribers meter ||2 is traced from the negative pole of battery through the winding of meter H2, a front contact of register control relay |09, front contact of cutoff relay |01, sleeve terminal and brush |03' of line-lnder LF-L conductor |21, left front contact of relay |05, front Contact of the right continuity spring of relay |08, front contact of the left continuity sp-ring of relay H3, and through resistance lamp |5 to the positive pole of boosterbattery. When ground is disconnected from the brush of interrupter 220,' one-half second after relay |08 operates, relays ||3 and |09 and meter ||2V are released. No further operation of meter ||2 is possible since relay |08 is locked under control of sleeve relay |05. Relays ll'and- |08, as controlled by interrupter drums 221 and 228 prevent the false operation of the calling subscribers meter in case relay |04 is temporarily operated in response to a line or trunks busy signal. The release of relay H3 extends the connection from sleeve conductor |21 to ground at the outer right frontcontact of relay |05.

When the connection is released at the calling station, the holding ground potential is disconnected from sleeve conductor |29 to cause the release of relay |05 and the return of selectors S-l and S-2 to normal; and when the receiver is replaced at the called station, the connector C I returns to normal, the return of the selector and connector switches being eected -in Wellknown manner. The release of relay |05 causes the release of Vrelays |08 and |01 and the return of the line nder LF-I to normal.

If the called station is not in the same oice as the calling station A, the connection from the calling line is extended through brushes |2| and |22 of selector S| over trunk |38, through back 25 contacts of relay 205 to the windings of line relay 20| of repeater R--|. The operation of relay 20| closes a circuit for operating the slow-torelease relay 202. Relay 202 connects ground through its inner left front contact over conductor 230, through the outer left back contact or' relay 205 and the back contact of the continuity spring oi relay 203, over sleeve conductor 2|9, to brush |23 of selector S-l to hold the selector and thence to sleeve conductor |20 t0 operate relay |05 of trunk CT. Relay |0u` is marginal and does not operate when ground is connected to conductor |20. The operation of relay |05 connects ground to conductor |21 to hold the line nder LF-l and to hold the cutoff relay |01. The aforementioned operation of relay 202 alsol closes a circuit for operating relay 203, closes a bridge across the conductors of trunk.T-| to operate the line relay (not shown) of. the` distant incoming selector S-3, and closes circuits for' energizing the right winding of each of'relays 204 and 200. The circuit for operating relay 203 is traced from ground at the outer left frontV contact of relay 202, through the outer right back contact of relay 205, and through the winding of relay 203 to battery. The bridge acrossY the conductors of trunk T--l is traced from conductor 252 thro-ugh the left front ccntact of relay 20|, lower winding of impedance coil 2 |1, inner left back contact of relay 205, left winding of relay 204, back contact of relay 208, outer right front contact of relay 202 to conductor 25|. Relay 204 does not operate at this time since the current through the left winding of this` relay is electromagnetically opposed to the current through its right winding. The circuit through the right Winding of relay 206 includes resistance 226 and, being marginal, relay 206 is not operated at this time.

The lineV relay 20| of repeater R---IA responds to each of the impulses created by the dialing of the second and succeeding digits of the called subscribers number, the opening and closing of its left front contact being effective to repeat the impulses'over trunk T-i to control the selective operation of the incoming selector 8 3, the intermediate selectors, if any, and the final selector C-2 to establish connection with the called line leading to the called station C. The alternateY release and reoperation of relay 20|v in response to the train of impulses created by the dialing of the second digit of the called subscribers number is also effective to cause the aclvance of register switch J-I to a corresponding position which is indicative of the zone in which the called line is located with respect to the calling line. If more than the first two digits were required to finally determine the zonein which the called line is located, the register switch might readily be modied by anyone skilled in the art to respond to any required number of digits. 'I'he release of relay 20| in response to the rst impluse of the second digit closes a circuit for operating relay 208 and a circuit for operating the stepping magnet 2|0 of switch J| and relay 209 in series. Relays 200 and 209 are both slow in releasing and remain operated until relay 20| reoperates after respo-nding to the last impulse of the digit. With relay 208 operated, the bridge across the trunk T-I is changed to exclude the lower winding of impedance coil 2|'| and the left winding of relay 204 and thereby improve the transmission of dial impulses over trunk T-I. The operation of magnet 2|0 advances the brushes of switch J-I into the first off-normal position. The off-normal contacts 2|4 are actuated as soon as the switch is moved out of normal position, the cir cuit for operating magnet 2|0 and relay 209 being thereby changed to include the front contact of relay 209 instead of the lower contacts of springs 2|4. Each succeeding release and reop.

eration of relay 20| in response to the impulses created by the dialing of the second digit causes a corresponding operation and release of magnet 2|0, the brushes of switch J-l being thereby advanced step-by-step into the position corresponding to the second digit. After all of the impulses in the train have been received by relay 20|, relays 208 and 209 release and the response of relay 20| to the succeeding trains of dial impulses is ineffective to cause the further advance of switch J-I.

The terminals of bank 2|| of switch J-I may be connected to the brushes of interrupter drums 232, 233, 234 and 235 as required for any particular trunking system. As shown in Fig. 2 the oir-normal teminals I, 6, 1, 8, 9 and 0 of bank 2I| are not connected to any of the interrupter drums, the selection of one of these terminals indicating a call to an olce in zone I; olf-'normal terminal 2 is connected to interrupter drum 232, the selection of terminal 2 indicating a call to zone 2; off-normal terminal 3 is connected to interrupter drum 233, the selection of terminal 3 indicating a call to zone 3; olf-normal terminal 4 is connected to interrupter drum 234, the selection of terminal 4 indicating a call to zone 4; and off-normal terminal 5 is connected to interrupter drum 235, the selection of terminal 5 indicating a call to zone 5. l

After the succeeding digits of the called subscribers number have been dialed and connection completed with the called line, the called station is signaled in usual manner; and when the receiver is removed thereat, the current over the conductors vof trunk T--I is reversed in wellknown manner, thereby causing the operation of relay 204 of repeater R-I. Relay 204 closes a circuit for operating relay 205. Relay 205 interchanges the connections between the talking conductors of trunk I 38 and the windings of relay 20| so that the circuit over these conductors and through the windings of polarized relay |04 of trunk CT--I is reversed and polarized relay |04 is operated. With relays 204 and 205 both operated, the supervisory bridge across the conductors of trunk T-I is traced from conductor 25|, through the outer right front contact of relay 202, right front contact of relay 204, left winding of relay 204, inner left front contact of relay 205, both windings of retard coil 2I'|, left front contact of relay 20|, to conductor 252 The high impedance of this bridge improves the transmission of speech current through condensers 240. The operation of relay 205 also closes a circuit for operating relay 2 I8; this circuit is traced from battery through the winding of relay 2 I8, right front contact of relay 203, outer right front contact of relay 205, to ground at the outer left front contact of relay 202. The operation of relay 205 also causes the release of relay 203 and the release of relay 203 opens the operating circuit for relay 2I8. Since relay 203 is slow in releasing, the incoming sleeve conductor 2|9 is momentarily connected through the left front contact of relay 203 and the left front contact of relay 2| 8 to the positive pole of booster-battery 220, the current over conductor 2 I9 being thereby increased sumciently to cause the operation of marginal relay |06 of trunk CT-I. With relays 203 and 2|0 released the sleeve conductor 2|9 is connected through the back contact of relay 203, outer left front contact of relay 205, right back contact of relay 2I8, left winding of relay 206, over conductor 239 to ground at relay 202. The current in this circuit through the left winding of relay 206 is electromagnetically opposed to the current through the right winding of relay 206 and relay 206 does not operate. The aforementioned operation of relay |06 of trunk CT-I, due to the momentary connection of booster-battery potential to conductor 2|9, is effective to short-circuit resistance 6 so that the current through the winding of relay |06 in series with the left winding of relay 206 is suflicient to hold relay |06 operated.

The aforementioned operation of relay |06 also closes a circuit for operating group relay 300 which is common to all of the trunk nders such as TF having access to the trunk CT-I. Relay 300 closes a circuit for operating the start relay of the rst idle trunk inder in the group and connects ground through its right front contact to the commutator segment of each of the trunk finders which corresponds to the level of the bank to which the trunk CT-I is connected. Assuming the .trunk finder TF to be the rst idlender in the group, the start relay 305 is operated; and assuming the trunk CT-I to be connected to terminals in the eighth-level of the bank, ground is connected to the eighth off-normal segmentof the vertical commutator 301. The operation of relay 305 closes a circuit for operating stepping relay 3|0; this circuit is traced from battery at the middle right back contact of relay 3|5, through the left winding of relay 3|0, back contacts of the rotary-stepping magnet 3|2 and vertical-stepping magnet 3| I, to ground at the outer right front contact of relay 305. The operation of relay 3|0 closes a circuit for operating the vertical-stepping magnet 3| I; this circuit is traced from battery at the middle right back con-V tact of relay 3|5, through the winding of magnet 3| I, left back contact of relay 3 I3, front contact of relay 3|0, to ground at relay 305. T'he operation of magnet 3| steps the brushes 30|, 302, 303 and 304 up to the rst level of the bank and commutator brush 308 into engagement with the frst-oiT-normal segment of the vertical coming: of relay- 3| 4 and closes a 1- temporary: holding circuitffor relay I I0; this fcircuitis traced from battery through thewinding'andginner left front contact of" relay I I0,I inner rig-htf front contact-f of relay |05, terminal and `brush 304 of `finder TF, y inner left front contact of relay`3 I 4, -toconductor 309, thence through ltheouter right front Contact@ of 4relay 3|5 and Windingof relay-SIB inpa-rallel mutator 301 .f The-verticalcfE-normal springs3| 9 y are actuated vas soon as the* shaft-f isfmove'd out? of normal position, closing'a circuitforl op'erat` ing relay 3I8; this circuit istraced fronr'battery.' throughthe Winding'of relay' 318; left back 'contact of relay 3I4', left frontcontact ofrelay 305, to ground at the upperfrontcontactfoiifthe'oirnormal springs 3|9'. If'the' terminals-tofW-hiclfr` trunk CT-I is connected are-not located in the rst level or" the bank, the operation-of` magnet 3II causes the release ofrelay 3I0f; andthe release of relay 3 I 0 causes the vrelease I of l magnet Y 3| Relay 3I0 Yand'magnet'3I I fcooper'atefto elevate the brushesfstep-bye-step4 in like manner until commutator brush 308'en'counters the iter-l minal 'which marks the level tovfwhich the trunk: CT--I isconnected; at Whiclrtime-'relay'lllis held operated and relay-3l3 operated by vthe-current in a circuit traced from ground atthe right front contact of group `relay 300, .throughYthe eighth oir-normal segment of#r commutaton 301- and brush 300, left' Windingtof -relay- 3|3, backv contact of rotary-'Steppngfmagnet-3I2, left Winding'of relay 3|0, to batteryfatthe middle right back contact of relay13 I In operating,relayl3 I 3* closes a holding. circuit from b'atteryat themid'dle' right back contact of relay I 5,'th'rough thewinding of vertical-stepping ma'g-net`3IiI; right -Winding and Vfront contact off'relayi3I3;` toground'at relay 305. Magnet SII isinsuncientlyenergized by the current in this circuit-to 'cause further vertical-stepping. Relay 3|3alsocloses Va circuit from battery through the windingfci the rotarystepping magnet SI2, left "front'contact of relay, 3I3, front .contact of relay 3I'0'; to ground' at relay 305. Th'e'operationof magnet 3|2 rotates the brushes into engagement with.' the rst'set of terminals in the level in which trunkfCTa-'I 'is connected. Y The circutthrough the left-Windingsof relays 3 |10 and 3 I 3 is opened atcommutatorfbrush 300 due to the rotation of thet brushshaft; If` the set of terminals toWhich" trunkCT-I'isconnected is not the r'st set `in`| the level, theropera-H tion of magnet 3|2 causes=therelease orelayf3|0`f and the release of relay 13'I0 'causes the .release yof magnet 3|2. Relay 3I'0"'and='magnet 3|'2r thereupon cooperate to rotate 'the'brushesstepbystep; until the brushes engage-the'terminals:toFWhichV the trunk CT-| is connected; at which' time a: circuit is closed from battery through the VWinding" of relay I I0 of trunk CT-|,` outer A'leftfrmit con'-v tact of relay |06, inner right-front.contactfiof` relay |05, terminal with which test brush." 304 fof? nder TF is in engagement,lftwinding of`relay\ 3|4, outer right back'E contact of relay`f3I'5fconductor 309, right Winding of relay 3I'0; to groundiat the inner right front contact-'ot relay 305: Re-'l lay I|0 is operated, relay 3I'0isheldoperated,A and relay 3I4 is sufficiently lenergized by the current inl this circuit to closeits-inner right front contact. Relay 3I4is`th`ereup`on completely operated by the current' in a circuit from battery through its right Windingand inner right frontY contact, through the front-'contact of rotarystepping magnet 3I2 and front contact of :relay 3|0, to groundat relay 305.` The vcomplete'operation of relay 3I4 closes'a circuit foroperating relay 3I5; this circuit is traced 'from batteryI through the leftI windingfof relay r3 I5',` outer `right front contact of relay 3|4, to groundat the upper front contact of the off-normal Springs-3|9r The aforementioned operation of relay .AI I 0 causes therelease of relays |06 and 300 The operation of relay 3 I 5 opensfthe-circuitthrough thele-ft Wind-gA with vthe rightwinding of'relay'lg-to ground at the inner right front contactfof relay 305. Relay.Y SIS operates to temporarilyA holdv relay 305 op.- erated. With-relays IIO and 3|4v operated, -the cut-off relay |01 of line |00- and theiholdin'gvrelay (notshown) of line nder LF-l'are held operated overe conductor |2'I, through the leftf front contact of frelay |05, inner right back?v contact of relay- 08,- impedance I I, inner right iront contacter-relay H0, terminal and brusht303V of nder TF, middle-*right front contact ofrelay- 3|4,l over conductor 324 ytoground at the back contact of relay 430 of yZone metering' control unit Z-I. Y

With' the brushes of `trunk finder TF in engagement with the set of terminals to Which trunk- CT-l is-connectecl, a circuit is. closed -for indicat-` ing to the repeater R-I that the Zonezmeteringfcontrol Vunit Z-I has been connectedfto 'trunk CT-I; this circuit is traced from booster-battery 440'in control unit Z-I, through the front con-V tact of slovv-to-releaserelayI BIB', outer left frontv contactof relay 3|4, brush' 302 and terminal-roti nder TF, sleeve conductor I29-'and brush L|231;I

of selector S-|, conductor 2I9,` backcontaet of re1ay-203, outer left frontcontact of relay 205,

right backcontact of relay ZIG'and-through the left Windingiof `relay 206;4 over fconductor239 to ground at the inner left front contact o frelay- 202. Relay 206 is sufficient-ly energized by-the; currentinlthis-circuit to: closefitsrinner right! front contact and the operation fof-f this relay-is thereupon completed by the energization yof its right Winding in an obvious circuit. Relay 206,

when completely operated, connects the brush of interrupter drum 229130 brush 2 I2 of switch J`-I and connects the sleeve conductor 2I9fthrough the right back contact of relay 2I5ya-nd the` left front contact of-relay 206 to conductor239, there-- by short-circuiting the left Windingof re1ay-20gfl relay 206 Ybeing held operated bythe-energizati'on" of its right Winding. p

The aforementioned operation of relay3I4 also causes-the'release of relay 3|8. Thereleaseof relay 3MB-opens theconnection between boosterbattery 440 and-1 conductor l 29` and closesV a--cir-z cuit-.from battery through the Winding: of relay 40| of controlunit Z-I- in parallelyvith the winding-of relay 405, over conductor'400, through the'back contact of relayx3|8, outerleft front contact ofI relay 3|4,lbrush 302 and terminal of" nder TF, over sleeve conductor |29,throu'gh brushl |23 fof selector S-'I, conductor12l9^of ree peater Rf-I, right back contact of relay-*2|5, left" front contact o f relay206,over conductor' 239 to ground at relayf202. the'current in--this circuitf but relay-A06 ismarginal and does not operate-at-fthisitirnefy With` relay 40| operated, ground is'connectedthrough its inner: rightV front contact to vconductor 30,9,V thereby short-circuiting the winding'ofrelay3l6`v and` the 'right Winding` ofv relay; 3I'0;" and "ground-f is furtherconnected over conductorr309through theyinner left` frontV contact ofrelayf3l'f4, rbrush 304 and terminalof finder TF; innerrightffrontf contactof-relay |05,` and through the'i'inner1'1eft` frontcontactofrelay -I I0 to Aholdvrelay' l'IIlop-f Relay 40| isf-operatedf by erated. The release of relay 3| 6 causes the release of relay 305 and the release of relay 305 causes the release of relay 3|3 and magnet 3|2.

' interrupter drum 229.

With relay 3| 5V operated, the start lead from group relay 300 is extended over conductor 330 to the next trunk nder in the group. After relay 305 releases, relay 3|4 is held operated by the energization of its lright winding in a circuit traced through its inner right front contact, over conductor 409 of control unit Z-I to ground at the outer right front contact of relay 40|.

-As soon after relay 206 of repeater R-I is operated, due to the interconnection of trunk CT-f-l With control unit Z-|, as the brush of interrupter drum 229 is connected to ground, relay 2|5 is operated if the called line is outside of zone I; the circuit for operating relay 2|5 is traced from battery through its Winding and left back contact, outer left back contact of relay 2|6, back contact of relay 209, off-normal terminal and brush of bank 2|2 of switch J-|, outer right front contact of relay 206, to ground through Relay 2|5 opens its operating circuit but is held operated through the left front Contact of relay 2| 5, brush and engaged terminal of bank 2H of switch J-|, to ground through the associated one of interrupter drums 232, 233, 234 and 235. The operation of relay 2|5 closes a circuit for operating relay 2|6 and relay 2|6 locks through its right front contact and the left front contact of relay 206, over conductor 239 to ground at relay 202. If the called line is in zone l, relays 2| 5 and 2|6 are not operated; but if the called line is in one of zones 2, 3, 4 or 5, the operation of relays 2|5 and 2 I6 closes and a circuit from booster-battery 220, through the left front contact of relay 2|6, outer right front contact of relay 2|5, conductor 2|9, brush |23 of selector S-I, conductor |29, terminal and brush 302 of trunk finder TF, outer left front contact of relay 3|4, back contact of relay 3|8 and over conductor 400 to cause the operation of marginal relay 406 of zone metering control unit Z-l. Relay 406 closes, at its front contact, a connection from the brush of interrupter drum 230, through the left back contacts of relays 404, 403, 402 and 408, and through the inner right back contact and winding of relay 401 to battery. As soonthereafter as the brush of interrupter drum 230 is connected to ground, relay 401 operates and locks solely under the control of drum 230. The operation of relay 401 causes the release of relay 406 and the release of relay 406 causes the operation of relay 402; the

circuit for operating relay 402 is traced from battery through its winding and right back contact and through the left front contact of relay 401 to ground at the back contact of relay 406. Relay 402 locks, over conductor 409, to ground at the outer right front contact of relay 40| and connects ground through its inner right front contact to terminal 4 of bank 422 of metering switch M-|, At the end of the first .25 second closure through interrupter drum 230, relay 401 releases, thereby again connecting the Winding of relay 406 to conductor 400. If the call is one to zone 2, the holding circuit for relay 2|5 of repeater R-I is opened at interrupter drum 232 so that relay 2|5 releases at the same time that relay 401 releases, to prevent the further operation of relay 406, but if the call is one beyond zone 2, relay 2|5 is held operated after relay 401 releases so that relay 406`is reoperated in the circuit which includes booster-battery 220 as hereinbefore traced. vAs soon after the second operation of Vrelay 406 as the brush of drum 230 tact of relay 406, left back contacts of relays 404 and 403, left front contact of relay 402, outer right back contact of relay 401, and through the inner right back contact and winding of relay 408. Relay 408 locks through its right front contact solely under the control of drum 230. The operation of relay 408 causes the release of relay 406 and the release of relay 406 causes the operation of relay 403. Relay 403 locks over conductor 409 and connects ground to terminal 6 of bank 422 of switch M-|. At the end of the second .25 second closure through interrupter drum 230, relay 408 releases, thereby again connecting the winding of relay 406 to conductor 400. If the call is one to zone 3, the holding circuit for relay 2|5 of repeater R-I is opened at interrupter drum 233, and relay 2|5 releases at the same time that relay 408 releases, to prevent the further operation of relay 406, but if the call is beyond zone 3, relay 2|5 is held operated after relay 408 releases so that relay 406 is operated a third time in the circuit from booster-battery 220. As soon after the third operation of relay 486 as the brush of drum 230 is again connected to ground, relay 401 is reoperated by the current in a circuit which` includes the front contact of relay 406, the left back con-l tact of relay 404, the outer left front contact of relay 403, and the left back contact of relay 408. Relay 401 again locks directly under the control of drum 230 and causes the release of relay 406. The release of relay 406 closesv a circuit for operating relay 404, which circuit includes the inner right front contact of relay 403, the left front contact of relay 401 and the back contact of relay 406. Relay 404 locks over conductor 409 and connects ground to terminal 8 of bank 422 of switch M-I. At the end of the third .25 second closure through interrupter drum 230, relay 401 releases, thereby again connecting the Winding of relay 406 to conductor 400. If the call is one to zone 4, the holding circuit for relay 2|5 of repeater R-I is opened at interrupter drum 234 and relay 2|5 releases, at the same time that relay 401 releases, to prevent the further operation of relay 406; but if the call is beyondzone 4,

relay 2|5 is held operated after relay 401 Vreleases so that relay 406 is operated a fourth time in the circuit from booster-battery 220. As soon after the fourth operation of relay 406 as the brush of drum 230 is again lconnected to ground, relay 408 is reoperated by the current in a circuit which includes the front contact of relay 406, the left front contact of relay 404, the outer right back contact of relay 401. Relay 408 again locks directly under the control of drum 230 and causes the release of relay 406. Relay 406 closes a circuit for operating relay 405; this circuit includes the inner left front contact of relay 404, the left front contact relay 408 and the back contact of relay 406.v Relay 405 locks over conductor 409 and connects ground to terminal l0 of bank 422 of switch M-l. VThe re lease of relay 408 when the fourth closure through drum 230 is ended again connects the Winding of relay 406 to conductor 400, but since the repeater R-l is arranged for use in a system having but ilve zones, the holding circuit for relay 2|5 opened at interrupter drum 235 and relay 2|5 releases at the same time that relay 408 releases so' that thereisno furtherfoperation of relay 406.

The Zone within which the called line is located having been registered inthe zone metering control unit Z-l by the operation of none, one, two, three or four of the register relays 402', 403, 404 and 405, the unit Z-I is prepared to control the operation of the calling subscribers meter accordingly. With relay |04 of trunk CT-I operated due to the reversal of the current through its windings in response vto Ythe answer of the `called subscriber as hereinbe'fore described and with the brushes of trunkfmder TF in engagement with the set of terminals to which trunk CT-| is connected, a circuit Vis closed for operating relay 3|1; this circuit is traced from battery through the winding of relay 3|'|, brush 30| and terminal of inder TF, front contact of relay |04, to ground at the outer right iront contact of relay ||0. As soon thereafter as the brush of interrupter drum 221 is connected to ground, a circuit is closed from this ground, through the back Contact of relay 4| l, outer left back contact of relay 4|2, front contact of relay 3|1, right back contactof relay 4|2, and through the right windirng of relay 4|! to battery. Relay 41| is operated by the current through its right winding, thereby connecting its left winding and the winding of relay 4|2 through the left front contacts of relay-4H to the brush of interrupter drum 228. When the brush oi drum 228 .is connected to ground, approximately two seconds after relay 4H is operated, relay 4|2 operates and relay 45| is held operated by the energization of its left winding. Relay 4|2 locks over conductor 400, independent of drum 228; but relay 4|| releases when the closure through drum 228 terminates. Relay 452 closes a circuit for operating relay 453; this circuit is traced from battery, through the winding of relay 4|3, outer left iront Contact of relay 4|2, front contact of relay 3H, and through the outer right front contact of relay 4|2 to ground. Relay 4|3 locks in a circuit through its left front contact, brush and terminals to I0, inclusive, of bank 424 of switch M-I toy ground at the outer right front contact of relay 40|. Relay 4|3 closes a holding circuit for relay 40| and closes a connection from the winding of relay 4|4, through the inner left front contact of relay 40|, inner right front contact of relay 4|2, terminal and brush of bank 42| of switch M-I, outer left front contact of relay 40|, brush and terminal of bank 425 of switch M-l, outer right front contact of relay 413, to the brush of interruptor drum 4|5. The brush of interrupter drum 4|5 is connected to ground for .5 second once every second, and, as soon after relay 4|3 operates as the connection through drum 4|5 is closed` relay 4|4 is operated. The operation of relay 4|4 closes a circuit for operating the stepping magnet 420 of switch M-L When the closure through drum 4| 5 terminates, the release of relay 4|4 causes the release of magnet 420.

F The release of magnet 420 advances the brushes of switch M-l out of position into engagement with terminal 2 in each of its banks. The switch M-i continues to advance under` Dhe control of interrupter drum 4|5 from position 2 into position The circuit for operating magnet 420 in each of positions 2, 4, 6, 8 and i0 is traced from the winding of magnet 420 through its interrupter contacts, terminal 2, 4, 3, B or l0 and brush of bank 42|., outer :left front contact of relay 40|, brush and correspondingterminal "of bankl 425,' and'through drum 4'I'5'to ground. The release of magnet 420 due tothe opening of its interrupter contacts in each of these -positions, advances the brushes to thenext succeeding position. The operation of magnet 420 in each of .positions 3, 5, and 0 depends upon the operation of the stepping relay 4|4, and the circuit for operating relay 4|4 in each of these positions is traced through the inner left front contact of relay 40|, terminal 3, 5, 1 or 9 and brush of bank 42|, outer left front contactof relay 40|, brush and corresponding terminal of bank 425, and through drum 4|5 to ground. The switch M-I is thus advanced two steps for each closure through drum 4|5 until position 1|| is reached. After reaching position stepping relay 4|4 is operated once every thirty seconds under control oi interrupter drum M6, the brush of .drum 4|3 being connected to groundonce every thirty seconds. The circuit for operating relay 4|4 is traced from its winding through the inner left front contact of relay 40|, each of terminals to 2|, inclusive, and brush of bank 42|, outer left front contact of relay 40|, brush and corresponding one of terminals to 2|, in-

elusive, of bank 425, to the brush Vof drum 4|5. With switch M-l in position 22, a circuit is closed 'through brushes 42| and 425 for operating relay 4| 0. Relay 4|0 locks over conductor 400 and closes a circuit for operating magnet 420; the opening of its operating circuit at its own contacts releases magnet 420 to advance switch M-l to normal position. The advance of switch M| has, therefore, if uninterrupted until the first cycle of rotation is completed, measured ofi a period of time of fromve to ve Aandonehalf minutes, ive minutes being the unit for which the first charge is made.

While the switch M is being advanced from position to position relay 430 is operated .one vor more times to cause the operation or" the calling subscribers meter. On a call to Zone relay 430 is operated but once, and that in position 2 of switch M--I; on a call to' zone 2, relay 430 is operated twice, once in each of positions 2 4,5

and 4; on a call to Zone 3, relay 430 is `operated three times, once in each of positions 2, 4 and V0; on a call` to zone 4, relay 430 is operated four times, once in each of positions 2, 4, 0 and 0;

times, once in each of positions 2, 4, 5, 8 and I0. Each operation of relay 430 closes a circuit for operating meter control relay |00. With relay |09 operated, a circuit is closed from boosterand on a call to zone 5, relay 430 is operated ve 5o battery 440, through the right front contact of 55 :relay 430, conductor 324, middle right front contact of relay 3M, brush 303 and terminal of finder TF, inner right front contact of relay l0, impedance inner right back 4contact of relay |08, left front contact of relay |05, sleeve 60 conductor |21, brush |03 o f line finder LF|, front contact of cut-off relay i0?, a iront contact of relay |09, and through the winding of meter |I2 to the negative pole kof battery. The

meter I2 is thus operated to register one charge c5` for each operation of relay 430. r the call isi released before switch M-I completes its first cycle, relay 4|3 holds relay 40| until the charging operation is completed, that is, until switch M-l has advanced beyond position I0. If the connection is continued after the first measured unit of viive minutes, the continued operation of relay 40| causes switch M-IY to start a new cycle of operation and repeat theoperationof ,relay 430Mand meter |f|2gas described." On vthe '15 second and succeedingcycles the 'magnet'420 `of switch M-| is immediately operated in position 2| to advance the switch to position 22 without Waiting for the closure through interrupter drum 4|6,'it being unnecessary to allow for an immediate advance from position to position 2 on succeeding cycles as on the iirst cycle. The circuit for operating magnet 420 in position 2| of succeeding cycles is traced through the brushA and terminal 2| of bank 423 to ground at the front contact of relay 4|9.

When the connection is released by the calling subscriber relay |04 of trunk CT-| and relay 20| of repeater Rf-I release. The release of relay 20| causes the release of relay 202. With relay 20| released, the bridge across the conductors of trunk T--I is opened thereby releasing the succeeding switches in the completing train in usual manner. The release of relay 202 also causes the release of relays 206 and 2|6 and the operation of release magnet 2|3 of switch J-|. The operation of magnet 2|3 causes the brushes of switch J-| to be restored to normal, whereupon magnet 2| 3 releases. The release of relay 204, upon opening of the bridge across trunk T-I, causes the release of relay 205. The holding ground is disconnected from sleeve conductor 2| 9 when relay 202 releases, so that relay |05 of trunk CT-l and relay 40| of control unit Z-l are both released unless temporarily held while switch M-I is being advanced beyond position |0. With holding ground potential disconnected from conductor 2| 9 at the repeater, and with relay 4|3 of control unit Z-l released, relays |05 and 40| are released and the selector S-l is restored to normal in usual manner. The release of relay |05 causes the release of the cut-off relay |01, the release of relay 0, and the return of line nder LF-I to normal in usual manner. The aforementioned release of relay |04 causes the release of relay 3|1; and the release of relay 40| causes the release of relay 3| 4. The release of relay 3|4 closes a circuit for operating release magnet 320 of trunk nder TF. When the trunk finder reaches normal, the circuit for energizing magnet 320 and the circuit for holding relay 3| 5 operated are opened at springs 3|9. If relay 40| releases when switch M-I leaves position 0 or while switch M-l is in any of positions to 2|, inclusive, the circuit for operating magnet 420 is traced through the inner left back contact of relay 40| and the brush of bank 42|, to ground at the outer left back contact of relay 40|.

To follow the operation of the system on a call originated at a hat-rate subscribers station, Fig. '.7 should be substituted for Fig. l. The line 100 is extended by the operation of a line iinde'r LF-2 in usual manner to a trunk CT-2 and' an associated rst selector S-5. The selector S-5 selectivelyV responds to the rst digit dialed to extend the connection to a succeeding local selector S-G or to a repeater such as R-I. A local call is completed through the switch S-S, intermediate selectors if any, and a connector C-4. On local calls no operation of the sub-'- scribers meter 1|2 is required and none takes place. Relay 105 operates on all calls as soon as holding ground potential is connected to sleeve conductor 129 but relay 106 is marginal and operates only on an interoiice call in response to the connection of booster-battery 220 in repeater R-l to conductor 2 I9 when the vca lled subscriber answers, as hereinbefore described. VIn operat- Vaclaci ing; relay 106 short-circuitsresistance 1|6"s that relay 106 is held operated over conductors 129 and 2|9 to ground in repeater Rf-l when the booster-battery connection is opened and ground potential is again connected to conductor 2|9. The operation of relay 106 closes the circuit for operating group relay 300, whereupon an idle zone metering control unit such as Z-I is associated, by the operation of a trunk iinder 'I'F with the charging trunk CT--2 in the manner hereinbefore described. With unit Z| connected through finder TF to trunk CT--2, a circuit is closed for operating relay 1|0; this circuit is traced through the inner right front contact of relay 106, right front contact of relay 105, through brush 304 of trunk nder TF, inner left front contact of relay 3| 4, over conductor 309, to ground at the inner right front contact of relay 40|. Relay 1|0 locks to the same ground. The operation of relay 1 |0 causes the release of relay 106 and closes the circuit over which a signal is transmitted from boosterbattery 440 of zone unit Z-l to operate relay 206 of repeater R-L After the zone indication has been registered in unit Z-I, switch M-l is advanced to time the call and operate relay 430 as hereinbefore described. Each operation of relay 430 closes circuits for operating meter control relay 109 and meter 1|2. Release of the connection is similar to that on a call from a message-rate line.

In a system arranged according to Fig. 8, Vthe repeater R-2 shown in Fig. 5 and zone metering control unit Z-2 shown in Fig. 6 are arranged so as to cause the operative association of an idle zone metering control unit with the charging trunk CT| or CT-2 immediately upon extension of a call to the repeater without waiting for the answer of the called subscriber. Assuming a call to have been initiated at station A and the line |00 to have been extended through trunk CT-l and selector S-I over trunk |38 to repeater R-Z, relay is operated by the energization of its windings in series with the calling line |00. The operation of relay 50| closes a circuit for operating relay 502. Relay 502 closes a circuit through the right winding of relay 504, a circuit through the right winding of relay 506, a cir- .cuit for operating relay 503, and closes a bridge across conductors and 552 of outgoing trunk L,

T-Z to operate the line relay (not shown) of the incoming selector S-4 to which the trunk T-2 is connected at its distant end; this bridge is traced from conductor 55| through the outer right front contact of relay 502, back contact of relay 508, left winding of relay 504, inner left back contact of relay 505, lower winding of impedance 5| 1, and left front contact of relay 50| to conductor 552. Relay 504 does not operate at this time since the current through its left winding is electromagnetically opposed to the current through its right winding. Reay 50S is marginal and the energization of its right winding in series with resistance 526 is insuiilcient to cause its operation. Relay 502 also closes a circuit from ground through its inner left front contact, right back contact of relay 5|5, left winding and inner left back contact oi' relay 501, over conductor 5|9, through brush |23 of selector S--I to sleeve conductor |29, thence to battery through the winding of relay |05 in parallel with the winding of relay |06. Relays |05 and 501 are operated but relay |06 is marginal and the energizatlon of its winding in series with resistance ||6 is insufcient to cause its operation. Relay 501 locks 7'5y under control of relay 502, opens the circuit through its left winding and closes a connection vfrom conductor 519 through the inner left front contact of relay 501, left front contact of relay 503, left back contact of relay 518, right .back contact of relay 515 to ground at the inner left front contact of relay 502.

The aforementioned operation of relay 501 also opens the operating circuit for relay 503 but since relay 503 is slow in releasing, a .circuit is closed momentarily for causing the operation of relay 518; this circuit is traced from the Winding of relay 518, through the right front contact of relay 503, outer left front contact of relay 501 to ground at the outer left iront contact of relay 502. Whe-n relay 503 releases, relay 518 is released. While both of relays 518 and 503 are operated, a circuit is closed from the positive pole of booster-battery 520 through the left front contacts of relays 518 and 503, inner left front contact of relay 501, over conductor 519 to cause the operation of marginal relay of trunk CT-l. Relay 106 locks and causes the starting of a trunk nder TF to associate an idle Zone metering co-ntrol unit Z-2 with the trunk CT-l as hereinbefore described. When relay 503 releases, conductor 519 is connected through the inner left front contact of relay 501, back contact of relay 503, right front contact of relay 518, right back contact of relay 515, to ground at the inner left front contact of relay 502, so as to hold relays 105 and 106 operated. When relay 518 also releases, the connection between conductor 519 and ground is changed to include the right back contact of relay 518 and the left winding of relay 506 instead of the right front contact of relay 518. The current through the left winding of relay 505 is electromagnetically opposed to the current through the right winding of relay 506, so that this relay does not operate at this time.

When the trunk finder TF connects the control unit Z-2 to trunk CT-1, in response to the operation of relay 105, relays 110 and 314 are operated as hereinbefore described. The operation of relay 314 closes a circuit from boosterbattery 640 of unit 2 2, through the front contact of relay 3l8, outer left front contact of relay 314, brush 302 of trunk finder TF, over conductor 129, through brush 123 of selector S-1, conductor 519 of repeater R-Z, inner left front contact of relay 501, back contacts of relays 503 and 559, left winding of relay 506, right back contact of relay 515, to ground at the inner left front contact of relay 502. The current in this circuit through the left winding of relay 506 is now electromagnetically aiding the current through the right Winding of this relay so that relay 506 operates. With relay 506 operated, the sleeve conductor 519 is connected directly through the inner right front contact of relay 506 and right back contact of relay 515 to ground at relay 502, the left winding of relay 506 being short-circuited. Since resistance 526 is short-circuited at the outer right front contact of relay 506, relay 505 is held operated by the energization of its right winding. When relay 313 of trunk finder TF releases, a circuit is closed from ground potential connected to conductor 519, through brush 123 and sleeve conductor 129 of selector S-I, brush 302 of trunk finder TF, outer left front contact of relay 314, back contact of relay 318, over conductor 600, through the windings of relays 601 and 606. Relay 501 operates but relay 606 is marginal and does not operate. Relay 601 connects ground over conductor 609 to hold relay 314 operated and connects ground to conductor 309 to hold relay 110 of trunk CT--l operated.

The impulses created by the dialing of the second and succeeding digits oi the number of the subscribers station with which connection ris -desired are repeated by relay 501 over the trunk T-Z to selectively operate the selector S-f, any intermediate switches and the connector C-. The release oi relay 50! in response to the first impulse for each digit causes the operation of relay 508 and relay 508 remains .operated until all of the impulses in a train have been received. With relay 508 operated the bridge across trunk T-Z is traced directly from conductor` 55! through the outer right front contact o1" relay 502, front contact of relay 508, and left front contact of relay 501 to conductor 552. Relay 502 is slow in releasing and remains operated during the response of relay. 501 to the dial impulses.

The release of relay 551, in response to the dial impulses for the first digit dialed after the calling line is connected to repeater R-Z, also closes a circuit through the lower contact of the rotary off-normal springs 514 for operating rotary-stepping magnet 510 and relay 509. Relay 509 is a .slo-W-to-release relay and remains operated until all of the impulses in the train have been received. The operation of magnet 510 advances the brushes of switch J-2 from normal to the rst oil-normal position. Springs 514 are actuated when the brushes are moved out of normal position so that the circuit for holding relay 559 and for reoperating magnet 510 is traced through the front contact of relay 509 instead of through the lower contacts of springs 515. The magnet 510 releases when relay 501 reoperates and is reoperated and released under control of relay 5131 in response to each of the succeeding impulses in the train. The brushes of switc'h J-2 are thereby advanced to a position corresponding to the second digit of the called subscribers number, which digit indicates the zone within which the called line is located. The terminals of bank 511 of switch J--2 are cross-connected to the brushes of nterrupter drums 532, 533, 534 and 535 as required. Due to the actuation of springs 514, the response of relay 501 to the succeeding digits is ineffective to cause the further operation of switch J-2.

When relay 509 releases after the setting of switch J-Z and as soon thereafter as the brush of interrupter drum 529 is connected to ground, a circuit is closed, if the called line is located in one of zones 2, 3, 4 and 5, from drum 529 through the middle right front contact of relay 556, brush and off-normal terminal of bank 512 of switch J-Z, back contact of relay 509, outer left back contact of relay 516 and through the left back contact and Winding oi relay 515. Relay 515 operates and closes a circuit for operating relay 516. Relay 515 locks under control of relay 502 and closes a circuit from boostern battery 520, through the left front contact of relay 5i5, outer right front contact of relay 515, inner right front Contact of relay 506, over conducto-r 519, brush 123 of selector S-I, conductor 129, brush 302 of trunk nder TF, outer left front contact of relay 314, back contact of relay 318, over conductor 600 to the windings of relays 401 and 406. Relay 401 is held operated and relay 405 is operated by the current in this circuit. On a call to zone 1, relays 515 and 516 are not operated; but on a call to zones 2, 3, 4, o1" 5 relay 5I5 is locked through its left front Contact and brush 5I I of switch J-2 to that one lof'interrupter drums 532, 533, 534 or 535 which 'manner to that in which relays 406, 401 and 408 are operated under control of relays 2I5 and 2I6,

switch J-I and interruptor drums 230, 232, 233, 234 and 235 to cause the operation of Zone relays 402,403, 404 and 455 as hereinbefore described.

When the called subscriber answers, the current over trunk T--Z is reversed in the usual manner, thereby causing the operation of relay 504, the-current through the left winding being then electromagnetically aiding the current through its right winding. The operation of relay 504 causes the operation of relay 505 thereby reversing the current over trunk |38 to operate the polarized supervisory relay |04 of trunk CT-I. The operation of relay |04 closes a circuit from ground at the outer right front contact of relay II, through the front contact of relay |04 and brush 30| of trunk nder TF to operate relay 35'1. The operation of relay 3|'I places relays GII and SI2 under the control of interrupter drums 521 and 523 whereby not less than two seconds elapse before the advance of switch M-2 is initiated, relays 5II and GIZ being operated in a similar manner to that in which relays 4II and 4I2 are operated as hereinbefore described. With relays 60|, SI2 and 3II operated, the winding of stepping relay 5|4 is connected through terminal I and brush of each of banks 62| and 524 to the brush of interrupter drum 6| 5. The timing switch M-Z is thereupon advanced one cycle per five minutes under the control of interrupters 6|5 and BIS in similar manner to that in which switch M-I is advanced under control of interrupters 4I5 and 4|6 as Ahereinbeiore described. Relay 630 is operated to cause the operation of relay I 0S and meter I I2 according tothe Zone within which the called line is located in like manner to that in which relay 430 controls the metering circuit as hereinbefore described. Relay 6 I 9 performs a similar function to that of relay 4I9 as hereinbefore described.

When the connection is released by the calling subscriber, the repeaterR-Z and Zone metering control unit Z-Z are restored to normal in similar manner to that in which the repeater Rf-I and control unit Z--I are restored to normal as hereinbefore described. The' line finder LF-Z, selectors S-I and S-4 and connector C-3 are restored to normal in usual manner.

What is claimed is:

1'. In a multi-ofce telephone system, subscribers lines, means including a charging trunk for use in completing a talking connection between a calling one of said lines and any called line, another trunk for use in completing interoiiice calls, a meter for registering charges for calls originating over said calling line, zone metering apparatus for controlling the operation of said meter, switching means for operatively associating said zone metering apparatus with said charging trunk, and means associated with said other trunk for transmitting zone indicating signals to said zone apparatus.

-use in completing a talking connection between a calling one of said lines and a called line, an

outgoing trunk repeater for use in completing interoiiice calls, a meter for registering charges for calls originating over said calling line, zone metering apparatus for controlling the operation of said meter, switching means for operatively associating said zone metering apparatus with said charging trunk, and means in said repeater for initiating the operation of said switching means to associate said zone metering apparatus with said charging trunk.

3. In an automatic telephone system according to claim 2, means in said zone metering apparatus responsive to the association of said apparatus with said charging trunk for transmitting a signal to said repeater.

4. In an automatic telephone system according to claim 2, means in said zone metering apparatus responsive to the association of said apparatus and charging trunk for transmitting a signal to said repeater, and means in said repeater for thereupon transmitting to said apparatus signals indicative of the Zone to which a call through said repeater is directed.

5. In an automatic telephone system according to claim 2, means in said zone metering apparatus responsive to the association of said apparatus and charging trunk for transmitting a signal to said repeater, means in said repeater for thereupon transmitting to said apparatus signals indicative of the zone to which a call through said repeater is directed, and means responsive to the answer of the called station for initiating the operation of said apparatus to control the operation of said meter in accordance with the zone signals received from said repeater.

6. In a multi-zone telephone system, subscribers lines and stations in each of a plurality of Zones, a calling station, a meter for said calling station, a first selector switch, means including a charging trunk for connecting said Iirst selector switch with the line of the calling subscriber, other selector switches selectable by said first selector for use in completing local calls, outgoing trunks selectable by said first selector for use in completing interoiice calls, meter operating means individual to said charging trunk, zone metering cond trol units for use on interoice calls, switching means effective upon connection of said charging trunk with an outgoing trunk for connecting an idle one of said control units with said charging trunk, circuit means including a supervisory relay in said charging trunk for rendering the meter operating means in said charging trunk operatively efective on local calls, and means including said supervisory relay in said charging Atrunk for rendering the connected zone metering control unit operatively eifective on an interofice call in place of the operating means of said charging trunk.

'7. In a telephone system, according to claim 6, means associated with each of said outgoing trunks and operatively responsive to the connection of a Zone metering control unit with said charging trunk for transmitting to said zone metering control unit signals indicativev of the particular zone to which calls over said outgoing trunk are directed.

8. In a multi-zone telephone system, subscribers lines including a fiat-rate subscribers line, a service meter for said line for registering charges sforallcalls except local calls, a;rstselectorswitch Vfor use in completing both local and nter-cnice pleting interoice calls, zone metering lcontrol units for use on interoice calls, switching means operative upon connection of saidcharging trunk with an outgoing trunk for connecting ya zone metering control unit with said charging trunk, signal Vmeans individual to said' outgoing trunk 'operativelyresponsive to the connection ofsaid zone metering control unit with said charging trunk for indicating to said control unit the particular zone to which calls over said outgoing trunk are directed, and means individual to said Zone metering control unit for causing the operation of said meter one or more times, the number of meter operations being in accordance with the zone in which the called line is located as indicated by the signals received from the repeater connected to said charging trunk.

9. In an automatic telephone system, subscribers lines including a message-rate line and a nat-rate line, a meter for registering a charge for all calls from said message-rate line, a meter for registering a charge for all calls except local calls from said flat-rate line, means including a message-rate charging trunk and a first selector for use in completing both local and interoiiice calls from said message-rate line, means including a flat-rate charging trunk and another rst selector switch for use in completing both local and interoiiice calls from said flatrate line, other selector switches selectable by said rst selectors for use in completing local calls, outgoing trunks selectable by said rst selectors for use in completing interoffice calls, zone metering control units for use in operating said meters on interoiiice calls, finder switches, one for each of said zone metering control units, and means in each of said charging trunks operative in response to the selection of an outgoing trunk and inoperative in response to the selection of one of said other selector switches for setting in operation one of said finder switches to connect an idle zone metering control unit with said charging trunk.

10. In a multi-zone telephone system, subscribers lines including a message-rate line and a flat-rate line, service meters one for each of said lines, means including a message-rate charging trunk and a first selector switch for use in completing both local and interoice calls from said message-rate line, means including a flat-rate charging trunk and another first selector switch for use in completing both local and interoflice calls from said flat-rate line, other selector switches selectable by said rst selectors for use in completing local calls, outgoing trunks selectable by said first selectors for use in completing interofce calls, meter operating means individual to said message-rate charging trunk, Zone metering control u nits for use on interoffice calls, switching means operative upon connection of either one of said charging trunks with one of said outgoing trunks for connectingan idle one of said Zone metering control units with the connected charging trunk, signal means for said one of the outgoing trunks operatively responsive to the connection of said zone metering control unit with the connected charging trunk fior indicating to said control unit .the .particutering control unit adapted to cooperate with` the supervisory relay in either of ksaid charging for `rendering the zone metering `control unit operatively eiective on interoiiice calls.

11. In `a multi-office telephone system, subscribers lines, `'means including a charging trunk v for use on Aboth local .and interofce calls in completing a ftalking connection between a ,calling v-oneof .said lines and a called line, an outgoing trunk repeater for use in completing interofhce calls, a meter for registering charges for calls originating over said calling line, zone metering apparatus for controlling the operation of said meter, switching means for operatively associating said zone meteringl apparatus with said charging trunk, and means operative upon the interconnection of said charging trunk and outgoing trunk repeater for initiating the association of said zone metering apparatus with said charging trunk.

12. In a multi-ofice telephone system, subscribers lines, means including a charging trunk for use on both local and interoiiice calls in completing a talking connection between a calling one of said lines and a called line, an outgoing trunk repeater for use in completing interoice calls, a meter for registering charges for calls originating over said calling line, zone metering apparatus for controlling the operation of said meter, switching means for operatively associating said zone metering apparatus with said charging trunk, means in said outgoing repeater operative in response to the answer of the called subscriber for initiating the association of said zone metering apparatus with said charging trunk.

1-3. In a multi-ol'lice telephone system, subscribers lines, means including a charging trunk for use in completing a talking connection between a calling line and a called line, an outgoing trunk repeater for use in completing interofce calls, a service meter for the calling line, timing and meter operating apparatus for controlling the operation of said meter, switching means for operatively associating said timing and meter operating apparatus with said charging trunk, and means in said repeater for initiating the operation of said switching means to associate said timing and meter operating apparatus with said charging trunk.

14. In a telephone system according to claim 13, means associated with said timing and meter operating apparatus for transmitting to said repeater a signal indicative of the association of said apparatus with said charging trunk.

15. In a telephone system according to claim 13, means associated with said timing and meter operating apparatus for transmitting to said repeater a signal indicative of the association of said apparatus with said charging trunk, and means in said repeater for thereupon transmitting to said apparatus signals indicative of the charging rate for a call from the calling to the called station.

16. In a telephone system according to claim 13, means associated with said timing and merepeater a signal indicative of the association of said apparatus with said charging trunk,

vmeans in said repeater for thereupon transmitting to said apparatus signals indicative of the charging rate for a call completed through said repeater, and means responsive to the answer of the called station for initiating the operation 0f said apparatus to operate said meter n accordance with the indicated charging rate.

17. In a multi-zone telephone system, subscribers lines, means including a. charging trunk for use in completing a talking connection between a calling line and a called line, an outgoing trunk repeater for use in completing interoice calls, a service meter for the calling line, meter operating apparatus for controlling the operation of said meter, switching means for opwith said charging trunk, means in said repeater -f for thereupon transmitting to said apparatus signals indicative of the charging rate for a call completed through said repeater, means respon-V sive to the answer of the called subscriber for initiating the operation of said meter operating lo means to operate said meter in accordance with the indicated charging rate, and timing means for measuring unit periods of time during the maintenance of a connection and for controlling said meter operating means in accordance with l5 the duration of the call.

RAY. L. STOKELY. 

